\chapter{Introduction}

\section{VoIP Background}
\subsection{Industry Climate}
The telecommunications industry is shifting its focus away from traditional fixed networks and into mobile and broadband telephony. The broadband telephony market is currently small but undergoing rapid growth due to widespread broadband access and competitive pricing. Between 2005 and 2007 broadband voice access paths grew by 88\% \cite{www:oecd}. It is predicted that this growth will continue and broadband will become a mainstream voice access path.

Voice over Internet Protocol (VoIP) is the standard for transmitting voice over broadband. VoIP is the defacto standard technology for Private Branch Exchanges (PBX) in organisations, and VoIP international calling has been popular for some time because the costs are much lower than the PSTN or mobile networks. The popularity of VoIP for home use is also growing. The VoIP market is highly competitive \cite{www:oecd}, driving the cost of this service down. A common strategy providers employ to increase their profits is to maximise their operational efficiency. Operational efficiency is often measured by the ratio of staff to subscribers.

\subsection{Challenges and Considerations of Providing VoIP}
VoIP compresses digital audio samples and encapsulates them inside IP packets \cite{www:understandingSip}. User Datagram Protocol (UDP) is used to transport VoIP packets. UDP maximises the fast and efficient delivery of packets, making it ideal for real time traffic like voice. However UDP does not guarantee delivery and IP networks are not always ideal for carrying voice traffic.

VoIP is a demanding and critical service. As a real time application it is sensitive to network latency, packet loss and jitter. Furthermore there are subscriber expectations and in some countries government regulation that providers meet an acceptable level of Quality of Service (QoS).

VoIP adds further complexity to existing IP networks. VoIP traffic needs to be prioritised over other less time-critical traffic, but doing so can overwhelm network resources if not managed carefully.
 
Networks which carry VoIP must be carefully managed to provide acceptable QoS. Providers of VoIP services must accommodate for adverse network conditions through some combination of network over-provisioning, priority queuing and traffic engineering.

Despite the difficulties of delivering voice over IP, its attractive benefit is the increase of network utilisation.

\section{Managing and Monitoring VoIP Systems}

Management and monitoring of VoIP servers is a key to achieving QoS targets and operational efficiency. Typical server monitoring metrics such as interface throughput, up-time and memory usage are important, but in addition telephony-specific metrics need to be monitored by administrators. The telephony service and the underlying network should be monitored side by side.

We have identified a need for a management system designed specifically for VoIP. The system must manage both the telephony service and the network. Monitoring should occur in real-time to enable administrators to react immediately to changing network conditions. The system should allow a multiple service points to be monitored by a single person with ease.

The management system should reduce troubleshooting time by communicating vital information quickly and effectively. The monitoring information should be displayed in an intuitive way so that less skilled knowledge of VoIP technologies is required.

\section{LAMS - A VoIP Management Solution}

The complicated and detailed nature of VoIP monitoring has lead us to explore novel monitoring ideas that go beyond traditional text and 2D graphical representations of data \cite{www:necPBX} \cite{www:ciscoMon}. We searched for a solution that could maximise the volume of information conveyed, and present information in a intuitive way.

L3DGEWorld \cite{www:l3dge} is a network monitoring tool that represents network monitoring information as 3D virtual world. L3DGEWorld is a modification of Open Arena \cite{www:openarena}, an open source first person shooter game that makes use of Quake III game engine. It was developed by the Centre for Advance Internet Architectures (CAIA) at Swinburne University of Technology, originally for the purpose of monitoring network intrusion. It has since proved its versatility and been adapted to additional purposes, such as monitoring nodes of a super computer, and monitoring a distributed system of Uninterruptable Power Supplies.

Recognising the potential of L3DGEWorld to fulfil our requirements for monitoring a VoIP system, we used it as the core of our monitoring system: L3DGEWorld Asterisk Management System (LAMS). LAMS is our modification and extension of L3DGEWorld for monitoring distributed VoIP systems.


